Multiple plies of paper have been adhesively joined together in face-to-face relationship using techniques well known in the art. A particularly suitable and commercially successful technique is found in commonly assigned U.S. Pat. No. 5,143,776, issued Sep. 1, 1992 to Givens and incorporated herein by reference.
Joining multiple plies of paper together by embossing is also well known in the art. Embossing may be accomplished by adhesively joining mated distal surfaces of protuberances to form a laminate in knob-to-knob fashion. Knob-to-knob embossing is described in commonly assigned U.S. Pat. No. 3,414,459, issued Dec. 3, 1968 to Wells and incorporated herein by reference. An example of a pattern useful with knob-to-knob embossing is disclosed in commonly assigned U.S. Pat. No. Des. 239,137, issued Mar. 9, 1976 to Appleman and incorporated herein by reference. Appleman illustrates an embossed pattern found on commercially successful paper toweling. A variant type of knob-o-knob embossing is disclosed in U.S. Pat. No. 5,443,889, issued Aug. 22, 1995 to Ruppel et al.
Yet another type of embossing is nested embossing wherein the adhesively joined embossments are mutually offset as illustrated in U.S. Pat. Nos. 3,547,723, issued Dec. 15,1970 to Gresham; 3,556,907, issued Jan. 19, 1971 to Nystrand; 3,708,366, issued Jan. 2, 1973 to Donnelly; 3,738,905, issued Jun. 12, 1973 to Thomas; 3,867,225, issued Feb. 18, 1975 to Nystrand; and 4,483,728 issued Nov. 20, 1984 to Bauernfeind.
Yet another type of embossing is found in commonly assigned U.S. Pat. No. 5,294,475, issued Mar. 15, 1994 to McNeil and incorporated herein by reference. McNeil discloses dual ply lamination wherein a multi-ply laminate having a quilted cloth-like appearance and thick caliper is generated. In dual ply lamination, the embossed sites of one ply are oriented toward, compressed against, and joined to the non-embossed regions of the other ply.
One feature common to each of the three aforementioned embossing techniques is that in each, the embossments of the paper are deflected out of the plane of the paper by the protuberances of the embossing rolls. Adhesive which joins the plies is then applied to the embossments of the paper. The plies are then joined together in face-to-face relationship with the adhesive.
These techniques permanently join the plies in face-to-face relationship. Unfortunately none generate strength within the plane of the resulting laminate.
Embossing has also been used to impart aesthetic features to the resulting laminate as disclosed in GB 2 225 745A, published Nov. 18, 1992 to Chandler; U.S. Pat. Nos. 5,620,776 issued Apr. 15, 1997 to Schulz; and 4,978,565, issued Dec. 18, 1990 to Pigneul et al. Yet another technique for imparting aesthetic features to a laminate is printing, as disclosed in U.S. Pat. No. 5,209,953, issued May 11, 1993 to Grupe et al. Unfortunately, none of these methods for imparting aesthetically pleasing features to the laminate improves its strength.
Attempts to improve strength are illustrated by U.S. Pat. Nos. 4,522,863, issued Jun. 11, 1985 to Keck et al. and 4,915,993, issued Apr. 10, 1990 to Ten Wolde. Keck et al. and Ten Wolde disclose laminates having a middle layer comprising scrim or a grid-like reinforcing fabric. Both the scrim and reinforcing fabrics are distinct, separate, continuous plies added to the center of the laminate. Unfortunately, this approach to generating strength requires an additional ply to be interposed between two outer plies. The multiple plies still must be adhesively joined together to form the desired unitary laminate.
A commercially successful attempt to impart an essentially continuous network to a single ply of paper is found in commonly assigned U.S. Pat. No. 4,637,859, issued Jan. 20, 1987 to Trokhan, which patent is incorporated herein by reference. Trokhan discloses a paper made on a deflection member having an essentially continuous network and which is imprinted against a surface such as a Yankee drying drum to form an essentially continuous pattern.
Accordingly, it is an object of this invention to provide a laminate of a plurality of plies. Furthermore, it is an object of this invention to provide a laminate having the plies embossed together. It is finally an object of this invention to provide such a laminate with a continuous grid of adhesive which imparts strength to the laminate.